(1) Field of the Invention
The present invention relates to a permanent magnet, a production method of the same, and a material for the production, in which the permanent magnet includes a rare earth element.multidot.iron-permanent magnet, a rare earth element.multidot.iron.multidot.boron-permanent magnet and a rare earth element.multidot.iron.multidot.boron.multidot.nitrogen-permanent magnet superior in magnetic characteristics.
(2) Description of the Prior Art
Rare earth element.multidot.iron.multidot.born-permanent magnets are highly praised for the superior magnetic properties. Japanese Patent B-61-34242 discloses a magnetically anisotropic sintered permanent magnet composed of Fe-B(2-28 atomic %)-R(rare earth element, 8-30 atomic %). For the production, an alloy containing the above-mentioned components is cast, the cast alloy is pulverized to an alloy powder, and the alloy powder is molded and sintered. However, the method has defects that the pulverization of cast alloy is a costly step, and the product performances fluctuate between production batches. Japanese Patent B-3-72124 discloses a production method of an alloy powder for a rare earth element.multidot.iron.multidot.born-permanent magnet containing as the main component 8-30 atomic % of R (R is at least one rare earth element including Y), 2-28 atomic % of B and 65-82 atomic % of Fe. The method comprises steps of reducing the raw material powder containing the rare earth oxide, metal and/or alloy with metallic Ca or CaH.sub.2 reducing agent, heating the reduced material in an inert atmosphere, and removing byproducts by leaching with water. Problems accompanied by the method are that steps for removing byproducts and drying are necessary due to the employment of metallic Ca or CaH.sub.2 reducing agent, the obtained alloy powder is so fine as 1-10 .mu.m that the powder is readily oxidized in air and the oxygen-containing powder brings about inferior magnetic properties in the final product, careful handling of the powder necessitates equipments/steps for measuring, mixing and molding thereof under air-insulated conditions, which cause increase in the production cost. Requirement of a large amount of rare earth element also increases the production cost.